Farm animals and farm livestock, such as cattle, sheep, goats, and pigs, produce tens of millions of tons of waste each year. The disposal of such waste presents both problems and opportunities for farms and farmers ranging from the small family owned generational farm to the large corporate farms and for the feed livestock yards and food processing plants. The opportunity that presents itself is that if properly treated such waste can be transformed into valuable fertilizer for enhancing crop productivity and yields for that particular farm; or as a commodity that can be sold for profit. The ability to transform livestock waste into a salable commodity is of particular importance for small family-type farms whose profit margin is slight and tenuous. The problem faced by farms of all types is that local, state and federal laws, from township zoning ordinances to federal EPA and USDA regulations regulate and control the treatment, removal, disposal, reuse and recycling of animal waste. Numerous regulations and standards must be adhered to before, for example, livestock manure can be reprocessed for sale and use as natural fertilizer.
The prior art discloses a number of different tanks and drums for decomposing and processing waste and refuse material into useful soil fertilizer.
For example, the Emmet patent (U.S. Pat. No. 3,248,175) discloses a rotatable drum for manufacturing compost that includes a plurality of spaced openings at one end surface of the drum that can be selectively opened or closed to allow the discharge of the warm moist air or the air-steam mixture being piped through the drum. The conduit for the air extends in a u-shaped manner within the drum.
The Chester patent (U.S. Pat. No. 3,890,129) discloses a composting device that has open mesh side and end panels. For aerobic treatment, removable covers are placed over the open mesh side panels and when composting is completed, the covers are removed so that the composted material can be discharged through the mesh panels. For anaerobic treatment, both the mesh side panels and ends are covered to restrict airflow for such anaerobic treatment.
The Kaelin patent (U.S. Pat. No. 3,960,537) discloses a method and device for treating refuse and sludge and includes a chamber having an upper inlet aperture for receiving the material to be treated and a lower outlet aperture for discharge of the material. Sets of gas distributor blades are axially disposed along a vertical shaft for introducing a gas mixture into the chamber for treating the material.
The Terry patent (U.S. Pat. No. 4,024,219) discloses a drum for aerobic processing of waste material and includes a chamber through which a horizontal shaft extends, and projecting from the shaft are three vanes for effecting mixing and processing of the material.
The Cook patent (U.S. design Pat. No. 352,580) discloses a double drum design wherein two drums are mounted on a stand side-by-side for composting material.
The Kakuk et al. patent (U.S. Pat. No. 5,432,088) discloses a bin for aerobic composting that includes a plurality of horizontal mixing and aeration slots through which an implement, such as a garden tool, can be inserted for effecting the mixing of the material held within the bin.
Despite the ingenuity of the above devices, there remains a need for a continuously operable aerobic digester that can expedite the process of transforming waste material continually fed therein to safe and useful fertilizer.